Chestnut Shortbread Cookies With Candy Cap Mushrooms

Lightly nutty and sweet, these chestnut shortbread cookies are made with foraged chestnut flour. Candy cap infused sugar gives them a delicious maple flavor.

This fall I foraged a huge basket of chestnuts. This little corner of the PNW has an abundance of wild chestnut trees, and after a strong windstorm in autunm the ground is covered under trees.

Their prickly shells burst open when they fall, releasing the plump chestnuts inside. You have to be quick though, because the squirrels love them too!

Fresh chestnuts are a treat when roasted, but to preserve them, I roast them and grind them into flour. Chestnut flour is high in starch, gluten-free, and tastes lightly nutty and sweet.

It’s similar in texture to acorn flour, but without any bitterness. Just like acorn flour, chestnut flour is a nutrious, versatile flour that can be used to make cakes, cookies, pancakes, etc.

Since it’s gluten-free, chestnut flour is great in shortbread cookies with. These cookies taste nutty, sweet, with a delicous maple flavor and aroma from candy cap mushrooms. My daughter loves these and they make great additions to holiday cookie tins.

How To Make Chestnut & Maple Shortbread Cookies

Make Chestnut Flour

First, you will need to roast about 1.5 pounds of chestnuts and grind them into flour. This step takes a little time, so it’s best to do ahead of time.

To make flour, make an X cut on the side of each chestnut. Place the chestnuts cut side up on a tray, and bake in the oven at 350ºF for 12-15 minutes or until the peels have curled open and the inside is lightly golden brown.

Remove the chestnuts from the oven and allow to cool until you can handle them. Peel off and discard the shells. Place the roasted chestnuts in a food processor and grind until you get a course meal.

Spread the chestnut meal on a tray and dehydrate in the oven at the lowest setting or in a dehydrator at 105ºF for 12 hours. Stir the chestnut meal every couple of hours to dry evenly.

Once completely dried, add the chestnut meal to a high speed blender and grind until you get a fine flour. Sift the flour before using.

Make Candy Cap Mushroom Sugar

Candy cap mushrooms (Lactarius rubidus) taste and smell like maple syrup when dried. The easiest way to use them in baking is to simply grind them into sugar.

Place about 1 cup of raw cane sugar in a blender, and add 4 to 6 dried candy caps. Blend until combined. Sift the sugar before using, and subsitute for regular sugar in recipes to add maple flavor. A little goes a long way, these are potent!

Note: If you don't have candy cap mushrooms, simply use maple sugar instead. Maple sugar can be purchased at specialty grocery stores in the baking aisle. The combination of chestnuts and maple just takes the shortbread to the next level. 

Make the Shortbread

Now that you have chestnut flour and candy cap sugar, it’s time make the shortbread cookies. It’s important to work with cold dough, otherwise the cookies will spread when baking. Work quickly, and return the dough to the fridge as needed to keep cold between cutting and shapping and again before baking.

1. Warm the butter to room temperature for easier mixing.
2. Sift chestnut flour, all-purpose flour and spices together in a bowl and set aside. In a medium sized bowl, add butter, candy cap sugar, and vanilla and use a fork or pastry whisk to mix until combined.
3. Add the flour mixture slowly and continue to mix with a fork until the flour disappears and the dough is smooth and crumbly. Mix until there are no hidden chunks of butter, but don’t overwork it.
4. Divide the dough in half and shape each half into a disc. Wrap the discs tightly with plastic wrap and refrigerate for 2 hours or until firm. The dough can be refrigerated overnight.
5. Remove one disc from the fridge and allow to soften slightly. Place dough between two sheets of parchment paper and use a rolling pin to roll the dough to about ¼ inch thickness. Use a cookie cutter to cut shapes. Place the cookies back in the fridge to chill before baking.
6. If desired, before baking stack the shapes and brush the edges with the beaten egg. Sprinkle with demerara sugar. Peel the cookies apart and arrange on a parchment-lined cookie sheet ½ inch apart. Sprinkle the tops with flaky sea salt.
7. Preheat oven to 350ºF. Chill the cookies in the fridge for 20-30 minutes before baking so they don’t spread when baking. Bake for 15 to 20 minutes, or until the edges just begin to turn golden brown. Allow to cool on cookie sheet until hardened.

FAQ’s

What Do Chestnuts Taste Like?

Chestnuts are a delicate, crumbly starch with a hint of sweetness. Roasted chestnuts are rich, sweet, and nutty. Chestnut flour has a sweet, nutty taste, similar to acorn flour in texture but without any bitterness.

Gluten-free, with high levels of starch, potassium, and magnesium, chestnuts are highly nutritious and a rich source of antioxidants, even after cooking.

Where Can You Find Chestnuts?

Chestnut trees, genus Castanea, are indigenous to Europe, Asia and North America. Chestnut trees used to grow in large groves in eastern North America. They were called the “redwoods of the East”.

However, in the early 1900’s, the chestnut blight killed the majority of the 4 billion chestnuts trees across America.

The state of Oregon has a growing amount of chestnut trees that have been bred to be free of chesnut blight. They can be found in the wild in the Northwest part of Oregon and into Northern California.

If you don’t have chestnut trees growing nearby, don’t worry! You can purchase them at most supermarkets and farmer’s markets in the fall.